This Week on perl5-porters - 10-16 February 2008
"So should we punt in this case and revert to the old warning for
"SvGAMAGICAL"? My personal opinion is to leave it. People doing
strange things should not be surprised by strange results." -- Rick
Delaney, debating the Principle of Least Surprise (or something like
that).
Topics of Interest
Stratus VOS patches
Paul Green delivered his work to make perl 5.8, 5.10 and blead work on
Stratus VOS. The main sticking points are a filename that begins with
a '-' (minus), and filenames longer than 32 characters.
Some of the remaining test suite failures were due to VOS's slightly
funky TCP stack implementation, and Paul was slightly suspicious that
one of the failures indicated a problem in VOS's implementation of
UDP.
Martien Verbruggen explained the finer points of POSIX's "ctime"
behaviour to help Paul understand another failure, and that %e would
be the best thing to use. Unfortunately, other so-called
POSIX-compliant platforms *don't* implement %e, so it can't be used in
perl's test suite.
http://xrl.us/bghyh
Paul later listed the remaining issues on Stratus VOS and was happy to
learn that in some ways VMS is even more restrictive than VOS.
20 levels!
http://xrl.us/bghyj
ext/Time/Piece/Piece.xs use of "strptime"
In the above process, Paul had a close look at "strptime" used in
"Time::Piece" and thought it looked suspiciously identical to
FreeBSD's own implementation, but it lacked the grace to acknowledge
FreeBSD with a copyright.
Jerry D. Hedden demanded it be pulled from the core. People explained
why this was not possible (modules check in, but they never check out)
and that the module had received Larry Wall's blessing of The Right
Way to do time manipulations. Other people complained that while the
module was useful, the name was too cutesy by half.
Matt Sergeant owned up to being the responsible party, and said he'd
reinstate the copyright, which probably was chopped in an edit by
mistake.
lost in the translation
http://xrl.us/bghym
Syntax proposal for matching balanced strings
Johan Vromans noted that 5.10 regexp enhancements had made it much
easier to write regular expressions that match balanced strings, but
that it would be nice to special-case the easy problems with some
syntactic sugar.
Abigail found three flaws in the proposal. David Nicol thought that it
would be better, on the Teach A Person to Fish principle, to provide a
good tutorial to help people figure out how to write the expressions
themselves.
http://xrl.us/bghyo
David then suggested an alternate syntax for matching balanced
strings, but no code. And I think "\R" already means something
Unicodish.
improved improvement proposal
http://xrl.us/bghyq
Show constant in "Useless use of a constant in void context"
Rick Delaney mentioned that he would like to see exactly which useless
constant was being used in void context, rather than the current vague
error message which isn't very helpful. To show he was serious, he
offered a patch that did just that. Rafael thought the idea was Good
and applied the patch.
Hugo van der Sanden listed a number of edge cases where this could
lead to trouble, but Rafael thought that people who triggered the edge
cases should probably know why they were triggering them, and Rick
agreed.
the error message is the Truth
http://xrl.us/bghys
Change 33302 breaks my Win32 build
Steve Hay noticed that change #33302 was falling over on Win32, with
even "miniperl" crashing. The problem was in pp_hot.c, where an
equality against "cLISTOP->op_last->op_type" was broken, because
"op_last", while not "NULL", was pointing out the window. Sven
Dowideit reported similar problems on Solaris.
http://xrl.us/bghyu
Change 33313 causing failures
Jerry D. Hedden reported a new failure in t/op/pat.t that manifested
itself when run with "TEST", but not in the harness. Much discussion
followed regarding how the TAP parser deals with garbage.
The failure in t/op/pat.t was resolved to most people's satisfaction.
The underlying problem was a typo: "$ = ~/.../" rather than "$ =~
/.../" and there was a bit of discussion about why that returns the
complement of 0.
http://xrl.us/bghyw
DTrace probes for bleadperl part 2
Sven Dowideit tried added more DTrace probes to perl, notably to track
SV allocations, and module loads but was still having trouble with
getting op.c to cooperate.
http://xrl.us/bghyy
Shell patterns are subject to tilde expansion
Nicholas Clark discovered a latent bug in Configure that would
manifest itself on a machine without a "csh" C shell installed. He was
rather surprised to trace the origin of the bug all the way back to
Perl 1, and defied anyone to find a more ancient bug.
Given the crappiness of "csh", the true miracle is that no-one
discovered this bug sooner.
http://xrl.us/bghy2
Slowdown of "sort keys %hash" under "use locale"
Marcus Holland-Moritz noticed that "use locale" prevented a hot C
routine from being cached during a sort of hash keys, and suggested a
simple solution, although he was uncertain whether it could break code
out in the wild.
Rafael thought the patch looked fine, and suggested that if a bug did
indeed emerge afterwards, it would probably be due to the magic
handling code (and so the fix would be made there).
cache dispenser
http://xrl.us/bghy4
Bug or feature in "B::class()"
Jim Cromie wondered why
my $start = B::main_start();
$start->class;
produced a "Can't locate object method" error message. Eirik Berg
Hanssen explained why and suggested an alternate syntax that would do
want Jim wanted. Joshua ben Jore said that it was that way because
no-one had bothered to implement it.
if you build it
http://xrl.us/bghy6
Testing "B"
Jim Cromie said that a full test suite for the "B" modules would be a
great idea. In the process of improving "B::Generate", he had begun
made a good start on doing just that. He posted his current work in
progress and asked if there was interest in having it in blead.
Michael G. Schwern made some very good suggestions on how to better
leverage the testing infrastructure to make Jim's work easier and
improve the quality of the diagnostics when things break.
Jimmy B Goode
http://xrl.us/bghy8
Assistance with IPC modules and perl 5.10
Tom Callaway wrote to say that he was preparing perl 5.10 for
inclusion in the upcoming Fedora 9 release, and was having troubles
with "IPC::ShareLite" and "IPC::SharedCache". This was holding up the
process and time was running out, which meant he'd have to go with
5.8.
That these two particular modules were deemed to be on the critical
path puzzled a number of the porters who had either never heard of
them or had only a vague idea what purpose they served. A careful
examination of the failures indicated that these two modules were in
fact optional, and weren't sufficient reason to block the Fedora
release.
Nevertheless, Tom wanted to know if and how they could be fixed. The
concensus was that it was a 32/64 bit issue rearing its ugly head.
Dave Rolsky was of the opinion that these two modules sucked so much
that no-one in their right mind should be using them.
memcached, memcached, memcached
http://xrl.us/bghza
Patches of Interest
"PERL_MAGIC_uvar_elem" should be 'u' in dump.c
Vincent Pit discovered an inconsistency between the magic type
"uvar_elem" and its symbolic name. He also wondered whether it was
even used any more. Rafael applied the fix and mentioned that "DBI"
and/or "Tk" use it.
http://xrl.us/bghzc
Is IPC/SysV/SysV.xs compiling?
Marcus Holland-Moritz wanted to know if Steve Peters and Jarkko
Hietaniemi were still seeing black smoke compiling this module. If
not, this would allow him to proceed in the release of a new version.
http://xrl.us/bghze
use svtype
Robin Barker straightened out the declaration of "sv_type" as an
"svtype" instead of the current mish-mash of "I32" and "U32" types,
and added a sprinkle of consting goodness into the mix. Applied by
Rafael.
http://xrl.us/bghzg
doio.c "Perl_my_lstat" revisited
Vincent Pit had a look at the implementation of "my_lstat" and
discovered that magic was called two times too many and could generate
a slew of superfluous warnings with "-l undef". He corrected that and
also fixed a test that was passing when it shouldn't. Steve Peters
thought the change looked good enough and applied it.
http://xrl.us/bghzi
Splitting OP_CONST
Vincent took Nicholas Clark at his word (from the pp_const, not, that,
hot thread) and split "OP_CONST" into two separate ops. He had it
running correctly on both threaded and non-threaded builds, although
no-one picked it up to apply it to blead.
what's a semaphore
http://xrl.us/bghzk
Updating "Thread::Semaphore" and "Thread::Queue"
Jerry D. Hedden cast his net wider in the threads infrastructure and
spent some time working with "Thread::Semaphore". After a couple of
false starts and doing battle with "Test::More" on 5.8.0, he was able
to release version 2.04, which Rafael applied to blead.
http://xrl.us/bghzn
Once that was out of the way, Jerry took a look at "Thread::Queue" and
added some useful functionality and a whole pile of tests.
http://xrl.us/bghzp
Jerry discovered that "Thread::Semaphore" will barf on non-numeric
parameters, but will happily accept "$sem->up(0.5)" or
"$sem->down(-1)". Whilst these could be construed as being a semaphore
that can't make up its mind and a semaphore being raised,
respectively, Jerry was inclined to classify them as errors as well.
If no-one voices objections soon, that's probably what such
shenanigans will become.
http://xrl.us/bghzr
Don't install threads files on non-threaded Perls
H.Merijn Brand thought that all the threads files that were installed
on a non-threaded build were pretty pointless, untidy and/or a waste
of space. So Jerry D. Hedden patched the installer to prevent that
from happening. Rafael Garcia-Suarez applied it, and H.Merijn
rejoiced.
Then he discovered another set of thready files and wondered if they
could be axed as well.
http://xrl.us/bghzt
New and old bugs from RT
More adventures on IRIX (#33849)
David Cantrell announced that he had warmed up his IRIX iron, and had
taken the previous suggestions and fixes out for a spin. He reported
that the compilation had proceeded somewhat further, but still wound
up crashing and burning.
Andy Dougherty, unfazed by such minor trivialities, moved onto Plan B,
which involves using "make minitest", to run a health check on
"miniperl". He warned that there may many spurious errors due to tests
relying on modules that have not yet been built but nevertheless may
provide some clues to what is going wrong.
Andy's Plan C would be to compile without "-O3" optimisation (his
initial suspicion being that the C compiler optimiser is getting
confused). Were David feeling particularly brave, he could pin-point
the offending file by compiling files with personalised optimisation
settings, and the resulting knowledge gleaned from the exercise could
be safely stowed away in the IRIX hints file.
Nicholas suggested David investigate "ccache" if he was serious about
trying this last approach.
the real question is, how many people still use IRIX?
http://xrl.us/bghzv
Use of inherited AUTOLOAD for non-method is deprecated (#47047)
Rick Delaney revived a dead bug that had slipped through the cracks in
the run-up to 5.10. Steve Peters applied it, and Rafael Garcia-Suarez
hastily unapplied it, since a minor detail that Rick overlooked in the
implementation caused segfaults on other platforms.
Rafael explained that the ultimate correct fix would add a lot of
make-work code and wasn't sure that the cost was worth it. Rick
concurred.
http://xrl.us/bghzx
"%^H" affecting outside file scopes (#50706)
Rick Delaney discovered that "%^H" hints could leak across file scopes
and thought that this wasn't right. He then created a small patch that
he thought should fix the problem. Rafael believed that Rick was
right, so he applied it.
http://xrl.us/bghzz
"goto" error? (#50742)
You cannot "goto" a subroutine declaration. This is by design.
http://xrl.us/bghz3
Bug fix in malloc.c (#50856)
Mark Noyes patched the perl memory management helper routine
"getpages_adjacent" to work around a bug that manifests itself on
Solaris with 5.6.1 and 5.8.8. No reports as to whether this is
(still)? a problem in 5.10 or blead.
http://xrl.us/bghz5
Perl5 Bug Summary
287 new + 1498 open = 1785 (Created: 6, Closed: 5)
http://xrl.us/bghz7
http://rt.perl.org/rt3/NoAuth/perl5/Overview.html
In Brief
Paul Marquess thanked Jan Dubois for spotting an omitted change to
"DB_File". He explained that the impact was purely cosmetic and would
do something about it the next time something major was scheduled.
http://xrl.us/bghz9
Rafael Garcia-Suarez applied Jerry D. Hedden's read-only variable
tests from last week.
http://xrl.us/bgh2b
Jerry also found an unused variable in perlio.c and Rafael applied
that as well.
less bloat
http://xrl.us/bgh2d
Jerry then needed help with a "threads::shared" code issue that works
on blead but warns on maint. Rafael solved it neatly by pointing out
that the code in question would never be backported to maint since the
change is technically a change in the API. And thus it could be
wrapped up in "#ifdef"s.
http://xrl.us/bgh2f
Nicholas Clark isolated an interesting self contained task dealing
with replacing two ops by one op, that would be a nice introduction
for someone wanting to get their hands dirty working on the internals.
Philippe Bruhat expressed interest, but then Nicholas spoiled the fun
by discovering that a one-character patch to opcode.pl solved the
problem nicely.
the art is knowing which one character to add
http://xrl.us/bgh2h
Robin Barker saw that the last run of "make regen_header" tweaked
pod/perlapi.pod and posted the changes in a patch. Unapplied.
why is this not automatic?
http://xrl.us/bgh2j
Abigail also thought that her TODO tests for issues relating to "keys
%+" does not return the correct keys (bug #50496) had been ignored.
Rafael replied that one of the non-TODO tests was also failing, so he
TODOified it as well, and applied it all in change #33313.
http://xrl.us/bgh2m
Abigail also tweaked perlfunc.pod regarding "%+d" (plus) "sprintf"
format specifiers. Accepted by Rafael.
http://xrl.us/bgh2o
Vincent Pit ran into some "Unbalanced string table refcount" errors on
a non-threaded blead, that Rafael fixed with change #33322.
you just have to ask
http://xrl.us/bgh2q
Daniel Frederick Crisman wrapped up the no link label on CPAN html
debate by suggesting that the finer points of POD are best discussed
on the "pod-people" mailing list.
http://xrl.us/bgh2s
Michael Schroeder asked whether Yves had been able to look at
"0"x51)=~/0{50}/ causing a panic on PPC bug (#50114).
lost IRL
http://xrl.us/bgh2u
In a similar vein, Jan Dubois wondered if his fix for bit-fields for
VC that would solve bug #50386 had been Warnocked.
http://xrl.us/bgh2w
Steve Hat noticed that change #33292 to bitfields caused compiler
warnings on Win32/VC6. He and Jan discussed the problem, which was
caused by different types ("int"s and "char"s) being used in
bit-fields. Steve cleaned everything up with change #33315.
http://xrl.us/bgh2y
About this summary
3-10 February 2008
http://xrl.us/bgh22
This summary was written by David Landgren. The in-laws are in town,
so this week's summary has even less error checking than usual. Please
forgive me if there are even more typos and wordos than usual.
Weekly summaries are published on http://use.perl.org/ and posted on a
mailing list, (subscription: [EMAIL PROTECTED]). The
archive is at http://dev.perl.org/perl5/list-summaries/. Corrections
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